1 /* DWARF2 exception handling and frame unwind runtime interface routines.
2 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 In addition to the permissions in the GNU General Public License, the
13 Free Software Foundation gives you unlimited permission to link the
14 compiled version of this file into combinations with other programs,
15 and to distribute those combinations without any restriction coming
16 from the use of this file. (The General Public License restrictions
17 do apply in other respects; for example, they cover modification of
18 the file, and distribution when not linked into a combined
21 GCC is distributed in the hope that it will be useful, but WITHOUT
22 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
23 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
24 License for more details.
26 You should have received a copy of the GNU General Public License
27 along with GCC; see the file COPYING. If not, write to the Free
28 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
33 #include "coretypes.h"
37 #ifdef __USING_SJLJ_EXCEPTIONS__
38 # define NO_SIZE_OF_ENCODED_VALUE
40 #include "unwind-pe.h"
41 #include "unwind-dw2-fde.h"
43 #include "unwind-dw2.h"
45 #ifndef __USING_SJLJ_EXCEPTIONS__
47 #ifndef STACK_GROWS_DOWNWARD
48 #define STACK_GROWS_DOWNWARD 0
50 #undef STACK_GROWS_DOWNWARD
51 #define STACK_GROWS_DOWNWARD 1
54 /* Dwarf frame registers used for pre gcc 3.0 compiled glibc. */
55 #ifndef PRE_GCC3_DWARF_FRAME_REGISTERS
56 #define PRE_GCC3_DWARF_FRAME_REGISTERS DWARF_FRAME_REGISTERS
59 #ifndef DWARF_REG_TO_UNWIND_COLUMN
60 #define DWARF_REG_TO_UNWIND_COLUMN(REGNO) (REGNO)
63 /* This is the register and unwind state for a particular frame. This
64 provides the information necessary to unwind up past a frame and return
66 struct _Unwind_Context
68 void *reg
[DWARF_FRAME_REGISTERS
+1];
72 struct dwarf_eh_bases bases
;
73 /* Signal frame context. */
74 #define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)
75 /* Context which has version/args_size/by_value fields. */
76 #define EXTENDED_CONTEXT_BIT ((~(_Unwind_Word) 0 >> 2) + 1)
78 /* 0 for now, can be increased when further fields are added to
79 struct _Unwind_Context. */
81 _Unwind_Word args_size
;
82 char by_value
[DWARF_FRAME_REGISTERS
+1];
85 /* Byte size of every register managed by these routines. */
86 static unsigned char dwarf_reg_size_table
[DWARF_FRAME_REGISTERS
+1];
89 /* Read unaligned data from the instruction buffer. */
94 unsigned u2
__attribute__ ((mode (HI
)));
95 unsigned u4
__attribute__ ((mode (SI
)));
96 unsigned u8
__attribute__ ((mode (DI
)));
97 signed s2
__attribute__ ((mode (HI
)));
98 signed s4
__attribute__ ((mode (SI
)));
99 signed s8
__attribute__ ((mode (DI
)));
100 } __attribute__ ((packed
));
102 static void uw_update_context (struct _Unwind_Context
*, _Unwind_FrameState
*);
103 static _Unwind_Reason_Code
uw_frame_state_for (struct _Unwind_Context
*,
104 _Unwind_FrameState
*);
107 read_pointer (const void *p
) { const union unaligned
*up
= p
; return up
->p
; }
110 read_1u (const void *p
) { return *(const unsigned char *) p
; }
113 read_1s (const void *p
) { return *(const signed char *) p
; }
116 read_2u (const void *p
) { const union unaligned
*up
= p
; return up
->u2
; }
119 read_2s (const void *p
) { const union unaligned
*up
= p
; return up
->s2
; }
121 static inline unsigned int
122 read_4u (const void *p
) { const union unaligned
*up
= p
; return up
->u4
; }
125 read_4s (const void *p
) { const union unaligned
*up
= p
; return up
->s4
; }
127 static inline unsigned long
128 read_8u (const void *p
) { const union unaligned
*up
= p
; return up
->u8
; }
130 static inline unsigned long
131 read_8s (const void *p
) { const union unaligned
*up
= p
; return up
->s8
; }
133 static inline _Unwind_Word
134 _Unwind_IsSignalFrame (struct _Unwind_Context
*context
)
136 return (context
->flags
& SIGNAL_FRAME_BIT
) ? 1 : 0;
140 _Unwind_SetSignalFrame (struct _Unwind_Context
*context
, int val
)
143 context
->flags
|= SIGNAL_FRAME_BIT
;
145 context
->flags
&= ~SIGNAL_FRAME_BIT
;
148 static inline _Unwind_Word
149 _Unwind_IsExtendedContext (struct _Unwind_Context
*context
)
151 return context
->flags
& EXTENDED_CONTEXT_BIT
;
154 /* Get the value of register INDEX as saved in CONTEXT. */
157 _Unwind_GetGR (struct _Unwind_Context
*context
, int index
)
162 #ifdef DWARF_ZERO_REG
163 if (index
== DWARF_ZERO_REG
)
167 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
168 gcc_assert (index
< (int) sizeof(dwarf_reg_size_table
));
169 size
= dwarf_reg_size_table
[index
];
170 ptr
= context
->reg
[index
];
172 if (_Unwind_IsExtendedContext (context
) && context
->by_value
[index
])
173 return (_Unwind_Word
) (_Unwind_Internal_Ptr
) ptr
;
175 /* This will segfault if the register hasn't been saved. */
176 if (size
== sizeof(_Unwind_Ptr
))
177 return * (_Unwind_Ptr
*) ptr
;
180 gcc_assert (size
== sizeof(_Unwind_Word
));
181 return * (_Unwind_Word
*) ptr
;
186 _Unwind_GetPtr (struct _Unwind_Context
*context
, int index
)
188 return (void *)(_Unwind_Ptr
) _Unwind_GetGR (context
, index
);
191 /* Get the value of the CFA as saved in CONTEXT. */
194 _Unwind_GetCFA (struct _Unwind_Context
*context
)
196 return (_Unwind_Ptr
) context
->cfa
;
199 /* Overwrite the saved value for register INDEX in CONTEXT with VAL. */
202 _Unwind_SetGR (struct _Unwind_Context
*context
, int index
, _Unwind_Word val
)
207 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
208 gcc_assert (index
< (int) sizeof(dwarf_reg_size_table
));
209 size
= dwarf_reg_size_table
[index
];
211 if (_Unwind_IsExtendedContext (context
) && context
->by_value
[index
])
213 context
->reg
[index
] = (void *) (_Unwind_Internal_Ptr
) val
;
217 ptr
= context
->reg
[index
];
219 if (size
== sizeof(_Unwind_Ptr
))
220 * (_Unwind_Ptr
*) ptr
= val
;
223 gcc_assert (size
== sizeof(_Unwind_Word
));
224 * (_Unwind_Word
*) ptr
= val
;
228 /* Get the pointer to a register INDEX as saved in CONTEXT. */
231 _Unwind_GetGRPtr (struct _Unwind_Context
*context
, int index
)
233 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
234 if (_Unwind_IsExtendedContext (context
) && context
->by_value
[index
])
235 return &context
->reg
[index
];
236 return context
->reg
[index
];
239 /* Set the pointer to a register INDEX as saved in CONTEXT. */
242 _Unwind_SetGRPtr (struct _Unwind_Context
*context
, int index
, void *p
)
244 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
245 if (_Unwind_IsExtendedContext (context
))
246 context
->by_value
[index
] = 0;
247 context
->reg
[index
] = p
;
250 /* Overwrite the saved value for register INDEX in CONTEXT with VAL. */
253 _Unwind_SetGRValue (struct _Unwind_Context
*context
, int index
,
256 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
257 gcc_assert (index
< (int) sizeof(dwarf_reg_size_table
));
258 gcc_assert (dwarf_reg_size_table
[index
] == sizeof (_Unwind_Ptr
));
260 context
->by_value
[index
] = 1;
261 context
->reg
[index
] = (void *) (_Unwind_Internal_Ptr
) val
;
264 /* Return nonzero if register INDEX is stored by value rather than
268 _Unwind_GRByValue (struct _Unwind_Context
*context
, int index
)
270 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
271 return context
->by_value
[index
];
274 /* Retrieve the return address for CONTEXT. */
277 _Unwind_GetIP (struct _Unwind_Context
*context
)
279 return (_Unwind_Ptr
) context
->ra
;
282 /* Retrieve the return address and flag whether that IP is before
283 or after first not yet fully executed instruction. */
286 _Unwind_GetIPInfo (struct _Unwind_Context
*context
, int *ip_before_insn
)
288 *ip_before_insn
= _Unwind_IsSignalFrame (context
);
289 return (_Unwind_Ptr
) context
->ra
;
292 /* Overwrite the return address for CONTEXT with VAL. */
295 _Unwind_SetIP (struct _Unwind_Context
*context
, _Unwind_Ptr val
)
297 context
->ra
= (void *) val
;
301 _Unwind_GetLanguageSpecificData (struct _Unwind_Context
*context
)
303 return context
->lsda
;
307 _Unwind_GetRegionStart (struct _Unwind_Context
*context
)
309 return (_Unwind_Ptr
) context
->bases
.func
;
313 _Unwind_FindEnclosingFunction (void *pc
)
315 struct dwarf_eh_bases bases
;
316 const struct dwarf_fde
*fde
= _Unwind_Find_FDE (pc
-1, &bases
);
325 _Unwind_GetDataRelBase (struct _Unwind_Context
*context
)
327 return (_Unwind_Ptr
) context
->bases
.dbase
;
331 _Unwind_GetTextRelBase (struct _Unwind_Context
*context
)
333 return (_Unwind_Ptr
) context
->bases
.tbase
;
337 #ifdef MD_UNWIND_SUPPORT
338 #include MD_UNWIND_SUPPORT
341 /* Extract any interesting information from the CIE for the translation
342 unit F belongs to. Return a pointer to the byte after the augmentation,
343 or NULL if we encountered an undecipherable augmentation. */
345 static const unsigned char *
346 extract_cie_info (const struct dwarf_cie
*cie
, struct _Unwind_Context
*context
,
347 _Unwind_FrameState
*fs
)
349 const unsigned char *aug
= cie
->augmentation
;
350 const unsigned char *p
= aug
+ strlen ((const char *)aug
) + 1;
351 const unsigned char *ret
= NULL
;
354 /* g++ v2 "eh" has pointer immediately following augmentation string,
355 so it must be handled first. */
356 if (aug
[0] == 'e' && aug
[1] == 'h')
358 fs
->eh_ptr
= read_pointer (p
);
359 p
+= sizeof (void *);
363 /* Immediately following the augmentation are the code and
364 data alignment and return address column. */
365 p
= read_uleb128 (p
, &fs
->code_align
);
366 p
= read_sleb128 (p
, &fs
->data_align
);
367 if (cie
->version
== 1)
368 fs
->retaddr_column
= *p
++;
370 p
= read_uleb128 (p
, &fs
->retaddr_column
);
371 fs
->lsda_encoding
= DW_EH_PE_omit
;
373 /* If the augmentation starts with 'z', then a uleb128 immediately
374 follows containing the length of the augmentation field following
378 p
= read_uleb128 (p
, &utmp
);
385 /* Iterate over recognized augmentation subsequences. */
388 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
391 fs
->lsda_encoding
= *p
++;
395 /* "R" indicates a byte indicating how FDE addresses are encoded. */
396 else if (aug
[0] == 'R')
398 fs
->fde_encoding
= *p
++;
402 /* "P" indicates a personality routine in the CIE augmentation. */
403 else if (aug
[0] == 'P')
405 _Unwind_Ptr personality
;
407 p
= read_encoded_value (context
, *p
, p
+ 1, &personality
);
408 fs
->personality
= (_Unwind_Personality_Fn
) personality
;
412 /* "S" indicates a signal frame. */
413 else if (aug
[0] == 'S')
415 fs
->signal_frame
= 1;
419 /* Otherwise we have an unknown augmentation string.
420 Bail unless we saw a 'z' prefix. */
425 return ret
? ret
: p
;
429 /* Decode a DW_OP stack program. Return the top of stack. Push INITIAL
430 onto the stack to start. */
433 execute_stack_op (const unsigned char *op_ptr
, const unsigned char *op_end
,
434 struct _Unwind_Context
*context
, _Unwind_Word initial
)
436 _Unwind_Word stack
[64]; /* ??? Assume this is enough. */
442 while (op_ptr
< op_end
)
444 enum dwarf_location_atom op
= *op_ptr
++;
445 _Unwind_Word result
, reg
, utmp
;
446 _Unwind_Sword offset
, stmp
;
482 result
= op
- DW_OP_lit0
;
486 result
= (_Unwind_Word
) (_Unwind_Ptr
) read_pointer (op_ptr
);
487 op_ptr
+= sizeof (void *);
491 result
= read_1u (op_ptr
);
495 result
= read_1s (op_ptr
);
499 result
= read_2u (op_ptr
);
503 result
= read_2s (op_ptr
);
507 result
= read_4u (op_ptr
);
511 result
= read_4s (op_ptr
);
515 result
= read_8u (op_ptr
);
519 result
= read_8s (op_ptr
);
523 op_ptr
= read_uleb128 (op_ptr
, &result
);
526 op_ptr
= read_sleb128 (op_ptr
, &stmp
);
562 result
= _Unwind_GetGR (context
, op
- DW_OP_reg0
);
565 op_ptr
= read_uleb128 (op_ptr
, ®
);
566 result
= _Unwind_GetGR (context
, reg
);
601 op_ptr
= read_sleb128 (op_ptr
, &offset
);
602 result
= _Unwind_GetGR (context
, op
- DW_OP_breg0
) + offset
;
605 op_ptr
= read_uleb128 (op_ptr
, ®
);
606 op_ptr
= read_sleb128 (op_ptr
, &offset
);
607 result
= _Unwind_GetGR (context
, reg
) + offset
;
611 gcc_assert (stack_elt
);
612 result
= stack
[stack_elt
- 1];
616 gcc_assert (stack_elt
);
622 gcc_assert (offset
< stack_elt
- 1);
623 result
= stack
[stack_elt
- 1 - offset
];
627 gcc_assert (stack_elt
>= 2);
628 result
= stack
[stack_elt
- 2];
633 _Unwind_Word t1
, t2
, t3
;
635 gcc_assert (stack_elt
>= 3);
636 t1
= stack
[stack_elt
- 1];
637 t2
= stack
[stack_elt
- 2];
638 t3
= stack
[stack_elt
- 3];
639 stack
[stack_elt
- 1] = t2
;
640 stack
[stack_elt
- 2] = t3
;
641 stack
[stack_elt
- 3] = t1
;
646 case DW_OP_deref_size
:
650 case DW_OP_plus_uconst
:
651 /* Unary operations. */
652 gcc_assert (stack_elt
);
655 result
= stack
[stack_elt
];
661 void *ptr
= (void *) (_Unwind_Ptr
) result
;
662 result
= (_Unwind_Ptr
) read_pointer (ptr
);
666 case DW_OP_deref_size
:
668 void *ptr
= (void *) (_Unwind_Ptr
) result
;
672 result
= read_1u (ptr
);
675 result
= read_2u (ptr
);
678 result
= read_4u (ptr
);
681 result
= read_8u (ptr
);
690 if ((_Unwind_Sword
) result
< 0)
699 case DW_OP_plus_uconst
:
700 op_ptr
= read_uleb128 (op_ptr
, &utmp
);
727 /* Binary operations. */
728 _Unwind_Word first
, second
;
729 gcc_assert (stack_elt
>= 2);
732 second
= stack
[stack_elt
];
733 first
= stack
[stack_elt
+ 1];
738 result
= second
& first
;
741 result
= (_Unwind_Sword
) second
/ (_Unwind_Sword
) first
;
744 result
= second
- first
;
747 result
= (_Unwind_Sword
) second
% (_Unwind_Sword
) first
;
750 result
= second
* first
;
753 result
= second
| first
;
756 result
= second
+ first
;
759 result
= second
<< first
;
762 result
= second
>> first
;
765 result
= (_Unwind_Sword
) second
>> first
;
768 result
= second
^ first
;
771 result
= (_Unwind_Sword
) first
<= (_Unwind_Sword
) second
;
774 result
= (_Unwind_Sword
) first
>= (_Unwind_Sword
) second
;
777 result
= (_Unwind_Sword
) first
== (_Unwind_Sword
) second
;
780 result
= (_Unwind_Sword
) first
< (_Unwind_Sword
) second
;
783 result
= (_Unwind_Sword
) first
> (_Unwind_Sword
) second
;
786 result
= (_Unwind_Sword
) first
!= (_Unwind_Sword
) second
;
796 offset
= read_2s (op_ptr
);
802 gcc_assert (stack_elt
);
805 offset
= read_2s (op_ptr
);
807 if (stack
[stack_elt
] != 0)
818 /* Most things push a result value. */
819 gcc_assert ((size_t) stack_elt
< sizeof(stack
)/sizeof(*stack
));
820 stack
[stack_elt
++] = result
;
824 /* We were executing this program to get a value. It should be
826 gcc_assert (stack_elt
);
828 return stack
[stack_elt
];
832 /* Decode DWARF 2 call frame information. Takes pointers the
833 instruction sequence to decode, current register information and
834 CIE info, and the PC range to evaluate. */
837 execute_cfa_program (const unsigned char *insn_ptr
,
838 const unsigned char *insn_end
,
839 struct _Unwind_Context
*context
,
840 _Unwind_FrameState
*fs
)
842 struct frame_state_reg_info
*unused_rs
= NULL
;
844 /* Don't allow remember/restore between CIE and FDE programs. */
845 fs
->regs
.prev
= NULL
;
847 /* The comparison with the return address uses < rather than <= because
848 we are only interested in the effects of code before the call; for a
849 noreturn function, the return address may point to unrelated code with
850 a different stack configuration that we are not interested in. We
851 assume that the call itself is unwind info-neutral; if not, or if
852 there are delay instructions that adjust the stack, these must be
853 reflected at the point immediately before the call insn.
854 In signal frames, return address is after last completed instruction,
855 so we add 1 to return address to make the comparison <=. */
856 while (insn_ptr
< insn_end
857 && fs
->pc
< context
->ra
+ _Unwind_IsSignalFrame (context
))
859 unsigned char insn
= *insn_ptr
++;
860 _Unwind_Word reg
, utmp
;
861 _Unwind_Sword offset
, stmp
;
863 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
864 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
865 else if ((insn
& 0xc0) == DW_CFA_offset
)
868 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
869 offset
= (_Unwind_Sword
) utmp
* fs
->data_align
;
870 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
872 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
874 else if ((insn
& 0xc0) == DW_CFA_restore
)
877 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
= REG_UNSAVED
;
885 insn_ptr
= read_encoded_value (context
, fs
->fde_encoding
,
887 fs
->pc
= (void *) pc
;
891 case DW_CFA_advance_loc1
:
892 fs
->pc
+= read_1u (insn_ptr
) * fs
->code_align
;
895 case DW_CFA_advance_loc2
:
896 fs
->pc
+= read_2u (insn_ptr
) * fs
->code_align
;
899 case DW_CFA_advance_loc4
:
900 fs
->pc
+= read_4u (insn_ptr
) * fs
->code_align
;
904 case DW_CFA_offset_extended
:
905 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
906 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
907 offset
= (_Unwind_Sword
) utmp
* fs
->data_align
;
908 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
910 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
913 case DW_CFA_restore_extended
:
914 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
915 /* FIXME, this is wrong; the CIE might have said that the
916 register was saved somewhere. */
917 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN(reg
)].how
= REG_UNSAVED
;
920 case DW_CFA_undefined
:
921 case DW_CFA_same_value
:
922 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
923 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN(reg
)].how
= REG_UNSAVED
;
929 case DW_CFA_register
:
932 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
933 insn_ptr
= read_uleb128 (insn_ptr
, ®2
);
934 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
= REG_SAVED_REG
;
935 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.reg
= reg2
;
939 case DW_CFA_remember_state
:
941 struct frame_state_reg_info
*new_rs
;
945 unused_rs
= unused_rs
->prev
;
948 new_rs
= alloca (sizeof (struct frame_state_reg_info
));
951 fs
->regs
.prev
= new_rs
;
955 case DW_CFA_restore_state
:
957 struct frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
959 old_rs
->prev
= unused_rs
;
965 insn_ptr
= read_uleb128 (insn_ptr
, &fs
->regs
.cfa_reg
);
966 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
967 fs
->regs
.cfa_offset
= utmp
;
968 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
971 case DW_CFA_def_cfa_register
:
972 insn_ptr
= read_uleb128 (insn_ptr
, &fs
->regs
.cfa_reg
);
973 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
976 case DW_CFA_def_cfa_offset
:
977 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
978 fs
->regs
.cfa_offset
= utmp
;
979 /* cfa_how deliberately not set. */
982 case DW_CFA_def_cfa_expression
:
983 fs
->regs
.cfa_exp
= insn_ptr
;
984 fs
->regs
.cfa_how
= CFA_EXP
;
985 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
989 case DW_CFA_expression
:
990 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
991 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
= REG_SAVED_EXP
;
992 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.exp
= insn_ptr
;
993 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
998 case DW_CFA_offset_extended_sf
:
999 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1000 insn_ptr
= read_sleb128 (insn_ptr
, &stmp
);
1001 offset
= stmp
* fs
->data_align
;
1002 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1004 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
1007 case DW_CFA_def_cfa_sf
:
1008 insn_ptr
= read_uleb128 (insn_ptr
, &fs
->regs
.cfa_reg
);
1009 insn_ptr
= read_sleb128 (insn_ptr
, &fs
->regs
.cfa_offset
);
1010 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
1011 fs
->regs
.cfa_offset
*= fs
->data_align
;
1014 case DW_CFA_def_cfa_offset_sf
:
1015 insn_ptr
= read_sleb128 (insn_ptr
, &fs
->regs
.cfa_offset
);
1016 fs
->regs
.cfa_offset
*= fs
->data_align
;
1017 /* cfa_how deliberately not set. */
1020 case DW_CFA_val_offset
:
1021 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1022 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1023 offset
= (_Unwind_Sword
) utmp
* fs
->data_align
;
1024 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1025 = REG_SAVED_VAL_OFFSET
;
1026 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
1029 case DW_CFA_val_offset_sf
:
1030 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1031 insn_ptr
= read_sleb128 (insn_ptr
, &stmp
);
1032 offset
= stmp
* fs
->data_align
;
1033 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1034 = REG_SAVED_VAL_OFFSET
;
1035 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
1038 case DW_CFA_val_expression
:
1039 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1040 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1041 = REG_SAVED_VAL_EXP
;
1042 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.exp
= insn_ptr
;
1043 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1047 case DW_CFA_GNU_window_save
:
1048 /* ??? Hardcoded for SPARC register window configuration. */
1049 for (reg
= 16; reg
< 32; ++reg
)
1051 fs
->regs
.reg
[reg
].how
= REG_SAVED_OFFSET
;
1052 fs
->regs
.reg
[reg
].loc
.offset
= (reg
- 16) * sizeof (void *);
1056 case DW_CFA_GNU_args_size
:
1057 insn_ptr
= read_uleb128 (insn_ptr
, &context
->args_size
);
1060 case DW_CFA_GNU_negative_offset_extended
:
1061 /* Obsoleted by DW_CFA_offset_extended_sf, but used by
1062 older PowerPC code. */
1063 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1064 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1065 offset
= (_Unwind_Word
) utmp
* fs
->data_align
;
1066 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1068 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= -offset
;
1077 /* Given the _Unwind_Context CONTEXT for a stack frame, look up the FDE for
1078 its caller and decode it into FS. This function also sets the
1079 args_size and lsda members of CONTEXT, as they are really information
1080 about the caller's frame. */
1082 static _Unwind_Reason_Code
1083 uw_frame_state_for (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
1085 const struct dwarf_fde
*fde
;
1086 const struct dwarf_cie
*cie
;
1087 const unsigned char *aug
, *insn
, *end
;
1089 memset (fs
, 0, sizeof (*fs
));
1090 context
->args_size
= 0;
1093 if (context
->ra
== 0)
1094 return _URC_END_OF_STACK
;
1096 fde
= _Unwind_Find_FDE (context
->ra
+ _Unwind_IsSignalFrame (context
) - 1,
1100 #ifdef MD_FALLBACK_FRAME_STATE_FOR
1101 /* Couldn't find frame unwind info for this function. Try a
1102 target-specific fallback mechanism. This will necessarily
1103 not provide a personality routine or LSDA. */
1104 return MD_FALLBACK_FRAME_STATE_FOR (context
, fs
);
1106 return _URC_END_OF_STACK
;
1110 fs
->pc
= context
->bases
.func
;
1112 cie
= get_cie (fde
);
1113 insn
= extract_cie_info (cie
, context
, fs
);
1115 /* CIE contained unknown augmentation. */
1116 return _URC_FATAL_PHASE1_ERROR
;
1118 /* First decode all the insns in the CIE. */
1119 end
= (unsigned char *) next_fde ((struct dwarf_fde
*) cie
);
1120 execute_cfa_program (insn
, end
, context
, fs
);
1122 /* Locate augmentation for the fde. */
1123 aug
= (unsigned char *) fde
+ sizeof (*fde
);
1124 aug
+= 2 * size_of_encoded_value (fs
->fde_encoding
);
1129 aug
= read_uleb128 (aug
, &i
);
1132 if (fs
->lsda_encoding
!= DW_EH_PE_omit
)
1136 aug
= read_encoded_value (context
, fs
->lsda_encoding
, aug
, &lsda
);
1137 context
->lsda
= (void *) lsda
;
1140 /* Then the insns in the FDE up to our target PC. */
1143 end
= (unsigned char *) next_fde (fde
);
1144 execute_cfa_program (insn
, end
, context
, fs
);
1146 return _URC_NO_REASON
;
1149 typedef struct frame_state
1155 long reg_or_offset
[PRE_GCC3_DWARF_FRAME_REGISTERS
+1];
1156 unsigned short cfa_reg
;
1157 unsigned short retaddr_column
;
1158 char saved
[PRE_GCC3_DWARF_FRAME_REGISTERS
+1];
1161 struct frame_state
* __frame_state_for (void *, struct frame_state
*);
1163 /* Called from pre-G++ 3.0 __throw to find the registers to restore for
1164 a given PC_TARGET. The caller should allocate a local variable of
1165 `struct frame_state' and pass its address to STATE_IN. */
1167 struct frame_state
*
1168 __frame_state_for (void *pc_target
, struct frame_state
*state_in
)
1170 struct _Unwind_Context context
;
1171 _Unwind_FrameState fs
;
1174 memset (&context
, 0, sizeof (struct _Unwind_Context
));
1175 context
.flags
= EXTENDED_CONTEXT_BIT
;
1176 context
.ra
= pc_target
+ 1;
1178 if (uw_frame_state_for (&context
, &fs
) != _URC_NO_REASON
)
1181 /* We have no way to pass a location expression for the CFA to our
1182 caller. It wouldn't understand it anyway. */
1183 if (fs
.regs
.cfa_how
== CFA_EXP
)
1186 for (reg
= 0; reg
< PRE_GCC3_DWARF_FRAME_REGISTERS
+ 1; reg
++)
1188 state_in
->saved
[reg
] = fs
.regs
.reg
[reg
].how
;
1189 switch (state_in
->saved
[reg
])
1192 state_in
->reg_or_offset
[reg
] = fs
.regs
.reg
[reg
].loc
.reg
;
1194 case REG_SAVED_OFFSET
:
1195 state_in
->reg_or_offset
[reg
] = fs
.regs
.reg
[reg
].loc
.offset
;
1198 state_in
->reg_or_offset
[reg
] = 0;
1203 state_in
->cfa_offset
= fs
.regs
.cfa_offset
;
1204 state_in
->cfa_reg
= fs
.regs
.cfa_reg
;
1205 state_in
->retaddr_column
= fs
.retaddr_column
;
1206 state_in
->args_size
= context
.args_size
;
1207 state_in
->eh_ptr
= fs
.eh_ptr
;
1212 typedef union { _Unwind_Ptr ptr
; _Unwind_Word word
; } _Unwind_SpTmp
;
1215 _Unwind_SetSpColumn (struct _Unwind_Context
*context
, void *cfa
,
1216 _Unwind_SpTmp
*tmp_sp
)
1218 int size
= dwarf_reg_size_table
[__builtin_dwarf_sp_column ()];
1220 if (size
== sizeof(_Unwind_Ptr
))
1221 tmp_sp
->ptr
= (_Unwind_Ptr
) cfa
;
1224 gcc_assert (size
== sizeof(_Unwind_Word
));
1225 tmp_sp
->word
= (_Unwind_Ptr
) cfa
;
1227 _Unwind_SetGRPtr (context
, __builtin_dwarf_sp_column (), tmp_sp
);
1231 uw_update_context_1 (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
1233 struct _Unwind_Context orig_context
= *context
;
1237 #ifdef EH_RETURN_STACKADJ_RTX
1238 /* Special handling here: Many machines do not use a frame pointer,
1239 and track the CFA only through offsets from the stack pointer from
1240 one frame to the next. In this case, the stack pointer is never
1241 stored, so it has no saved address in the context. What we do
1242 have is the CFA from the previous stack frame.
1244 In very special situations (such as unwind info for signal return),
1245 there may be location expressions that use the stack pointer as well.
1247 Do this conditionally for one frame. This allows the unwind info
1248 for one frame to save a copy of the stack pointer from the previous
1249 frame, and be able to use much easier CFA mechanisms to do it.
1250 Always zap the saved stack pointer value for the next frame; carrying
1251 the value over from one frame to another doesn't make sense. */
1253 _Unwind_SpTmp tmp_sp
;
1255 if (!_Unwind_GetGRPtr (&orig_context
, __builtin_dwarf_sp_column ()))
1256 _Unwind_SetSpColumn (&orig_context
, context
->cfa
, &tmp_sp
);
1257 _Unwind_SetGRPtr (context
, __builtin_dwarf_sp_column (), NULL
);
1260 /* Compute this frame's CFA. */
1261 switch (fs
->regs
.cfa_how
)
1263 case CFA_REG_OFFSET
:
1264 cfa
= _Unwind_GetPtr (&orig_context
, fs
->regs
.cfa_reg
);
1265 cfa
+= fs
->regs
.cfa_offset
;
1270 const unsigned char *exp
= fs
->regs
.cfa_exp
;
1273 exp
= read_uleb128 (exp
, &len
);
1274 cfa
= (void *) (_Unwind_Ptr
)
1275 execute_stack_op (exp
, exp
+ len
, &orig_context
, 0);
1284 /* Compute the addresses of all registers saved in this frame. */
1285 for (i
= 0; i
< DWARF_FRAME_REGISTERS
+ 1; ++i
)
1286 switch (fs
->regs
.reg
[i
].how
)
1291 case REG_SAVED_OFFSET
:
1292 _Unwind_SetGRPtr (context
, i
,
1293 (void *) (cfa
+ fs
->regs
.reg
[i
].loc
.offset
));
1297 if (_Unwind_GRByValue (&orig_context
, fs
->regs
.reg
[i
].loc
.reg
))
1298 _Unwind_SetGRValue (context
, i
,
1299 _Unwind_GetGR (&orig_context
,
1300 fs
->regs
.reg
[i
].loc
.reg
));
1302 _Unwind_SetGRPtr (context
, i
,
1303 _Unwind_GetGRPtr (&orig_context
,
1304 fs
->regs
.reg
[i
].loc
.reg
));
1309 const unsigned char *exp
= fs
->regs
.reg
[i
].loc
.exp
;
1313 exp
= read_uleb128 (exp
, &len
);
1314 val
= execute_stack_op (exp
, exp
+ len
, &orig_context
,
1316 _Unwind_SetGRPtr (context
, i
, (void *) val
);
1320 case REG_SAVED_VAL_OFFSET
:
1321 _Unwind_SetGRValue (context
, i
,
1322 (_Unwind_Internal_Ptr
)
1323 (cfa
+ fs
->regs
.reg
[i
].loc
.offset
));
1326 case REG_SAVED_VAL_EXP
:
1328 const unsigned char *exp
= fs
->regs
.reg
[i
].loc
.exp
;
1332 exp
= read_uleb128 (exp
, &len
);
1333 val
= execute_stack_op (exp
, exp
+ len
, &orig_context
,
1335 _Unwind_SetGRValue (context
, i
, val
);
1340 _Unwind_SetSignalFrame (context
, fs
->signal_frame
);
1342 #ifdef MD_FROB_UPDATE_CONTEXT
1343 MD_FROB_UPDATE_CONTEXT (context
, fs
);
1347 /* CONTEXT describes the unwind state for a frame, and FS describes the FDE
1348 of its caller. Update CONTEXT to refer to the caller as well. Note
1349 that the args_size and lsda members are not updated here, but later in
1350 uw_frame_state_for. */
1353 uw_update_context (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
1355 uw_update_context_1 (context
, fs
);
1357 /* Compute the return address now, since the return address column
1358 can change from frame to frame. */
1359 context
->ra
= __builtin_extract_return_addr
1360 (_Unwind_GetPtr (context
, fs
->retaddr_column
));
1364 uw_advance_context (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
1366 uw_update_context (context
, fs
);
1369 /* Fill in CONTEXT for top-of-stack. The only valid registers at this
1370 level will be the return address and the CFA. */
1372 #define uw_init_context(CONTEXT) \
1375 /* Do any necessary initialization to access arbitrary stack frames. \
1376 On the SPARC, this means flushing the register windows. */ \
1377 __builtin_unwind_init (); \
1378 uw_init_context_1 (CONTEXT, __builtin_dwarf_cfa (), \
1379 __builtin_return_address (0)); \
1384 init_dwarf_reg_size_table (void)
1386 __builtin_init_dwarf_reg_size_table (dwarf_reg_size_table
);
1390 uw_init_context_1 (struct _Unwind_Context
*context
,
1391 void *outer_cfa
, void *outer_ra
)
1393 void *ra
= __builtin_extract_return_addr (__builtin_return_address (0));
1394 _Unwind_FrameState fs
;
1395 _Unwind_SpTmp sp_slot
;
1396 _Unwind_Reason_Code code
;
1398 memset (context
, 0, sizeof (struct _Unwind_Context
));
1400 context
->flags
= EXTENDED_CONTEXT_BIT
;
1402 code
= uw_frame_state_for (context
, &fs
);
1403 gcc_assert (code
== _URC_NO_REASON
);
1407 static __gthread_once_t once_regsizes
= __GTHREAD_ONCE_INIT
;
1408 if (__gthread_once (&once_regsizes
, init_dwarf_reg_size_table
) != 0
1409 && dwarf_reg_size_table
[0] == 0)
1410 init_dwarf_reg_size_table ();
1413 if (dwarf_reg_size_table
[0] == 0)
1414 init_dwarf_reg_size_table ();
1417 /* Force the frame state to use the known cfa value. */
1418 _Unwind_SetSpColumn (context
, outer_cfa
, &sp_slot
);
1419 fs
.regs
.cfa_how
= CFA_REG_OFFSET
;
1420 fs
.regs
.cfa_reg
= __builtin_dwarf_sp_column ();
1421 fs
.regs
.cfa_offset
= 0;
1423 uw_update_context_1 (context
, &fs
);
1425 /* If the return address column was saved in a register in the
1426 initialization context, then we can't see it in the given
1427 call frame data. So have the initialization context tell us. */
1428 context
->ra
= __builtin_extract_return_addr (outer_ra
);
1432 /* Install TARGET into CURRENT so that we can return to it. This is a
1433 macro because __builtin_eh_return must be invoked in the context of
1436 #define uw_install_context(CURRENT, TARGET) \
1439 long offset = uw_install_context_1 ((CURRENT), (TARGET)); \
1440 void *handler = __builtin_frob_return_addr ((TARGET)->ra); \
1441 __builtin_eh_return (offset, handler); \
1446 uw_install_context_1 (struct _Unwind_Context
*current
,
1447 struct _Unwind_Context
*target
)
1450 _Unwind_SpTmp sp_slot
;
1452 /* If the target frame does not have a saved stack pointer,
1453 then set up the target's CFA. */
1454 if (!_Unwind_GetGRPtr (target
, __builtin_dwarf_sp_column ()))
1455 _Unwind_SetSpColumn (target
, target
->cfa
, &sp_slot
);
1457 for (i
= 0; i
< DWARF_FRAME_REGISTERS
; ++i
)
1459 void *c
= current
->reg
[i
];
1460 void *t
= target
->reg
[i
];
1462 gcc_assert (current
->by_value
[i
] == 0);
1463 if (target
->by_value
[i
] && c
)
1467 if (dwarf_reg_size_table
[i
] == sizeof (_Unwind_Word
))
1469 w
= (_Unwind_Internal_Ptr
) t
;
1470 memcpy (c
, &w
, sizeof (_Unwind_Word
));
1474 gcc_assert (dwarf_reg_size_table
[i
] == sizeof (_Unwind_Ptr
));
1475 p
= (_Unwind_Internal_Ptr
) t
;
1476 memcpy (c
, &p
, sizeof (_Unwind_Ptr
));
1479 else if (t
&& c
&& t
!= c
)
1480 memcpy (c
, t
, dwarf_reg_size_table
[i
]);
1483 /* If the current frame doesn't have a saved stack pointer, then we
1484 need to rely on EH_RETURN_STACKADJ_RTX to get our target stack
1485 pointer value reloaded. */
1486 if (!_Unwind_GetGRPtr (current
, __builtin_dwarf_sp_column ()))
1490 target_cfa
= _Unwind_GetPtr (target
, __builtin_dwarf_sp_column ());
1492 /* We adjust SP by the difference between CURRENT and TARGET's CFA. */
1493 if (STACK_GROWS_DOWNWARD
)
1494 return target_cfa
- current
->cfa
+ target
->args_size
;
1496 return current
->cfa
- target_cfa
- target
->args_size
;
1501 static inline _Unwind_Ptr
1502 uw_identify_context (struct _Unwind_Context
*context
)
1504 return _Unwind_GetIP (context
);
1508 #include "unwind.inc"
1510 #if defined (USE_GAS_SYMVER) && defined (SHARED) && defined (USE_LIBUNWIND_EXCEPTIONS)
1511 alias (_Unwind_Backtrace
);
1512 alias (_Unwind_DeleteException
);
1513 alias (_Unwind_FindEnclosingFunction
);
1514 alias (_Unwind_ForcedUnwind
);
1515 alias (_Unwind_GetDataRelBase
);
1516 alias (_Unwind_GetTextRelBase
);
1517 alias (_Unwind_GetCFA
);
1518 alias (_Unwind_GetGR
);
1519 alias (_Unwind_GetIP
);
1520 alias (_Unwind_GetLanguageSpecificData
);
1521 alias (_Unwind_GetRegionStart
);
1522 alias (_Unwind_RaiseException
);
1523 alias (_Unwind_Resume
);
1524 alias (_Unwind_Resume_or_Rethrow
);
1525 alias (_Unwind_SetGR
);
1526 alias (_Unwind_SetIP
);
1529 #endif /* !USING_SJLJ_EXCEPTIONS */